Assorted by materials:

A: carbonsteel (45# steel)

B: aluminumalloy 

C: nylon 

D: castings (castiron and ductile iron)

E: powderMetallurgy (iron and copper bases)

F: stainless steel

G: brass

H: bakelite 

Surface treatment: naturalanodize, black anodize, nickel electroless, chrome plating, zinc plating, zincyellow, high-frequency quenching etc.

Assorted by tooth types

A: square shape tooth  (MXL\XL\L\H\XH\XXH\SL\ modules belt)

B: T tooth (T2.5\T5\AT5\T10\AT10\T20\AT20)

C: HTD circle-arctooth (2M\3M\3GT\5M\5GT\8M\8YU\8MGT\14M\14MGT\20M)

D: STPD/STS: semi-circle-arc tooth (S3M\S4.5M\S5M\S8M\S14M)

E: sag peak tooth RPP (P3M\P5M\P8M\P14M)

F:other (POLYCHAIN-8MGT/14MGT, double helical tooth)